Protein-protein docking can be a complex and demanding task, requiring clean and protonated structures to ensure accurate results. Yet, one persistent challenge molecular modelers face is preparing their systems effectively before running docking workflows. SAMSON’s Hex Extension, designed for seamless protein docking, addresses this pain point by streamlining system preparation. Here, we’ll look into how SAMSON helps simplify this critical preparatory step.
Why Proper System Preparation Matters
System preparation is key to obtaining accurate docking results. Incomplete or unclean structures—such as those containing alternate atom locations, unnecessary water molecules, or unresolved atoms—can complicate docking calculations and produce misleading results. SAMSON offers tools to efficiently clean and ready your protein structures, saving time and improving outcome reliability.
How to Prepare the System with SAMSON
Here’s a step-by-step guide to preparing your docking system in SAMSON:
- Cleaning Up the Structure: Remove atoms with alternate locations, water molecules, monatomic ions, and any ligands that may interfere with docking. This reduces noise and potential inaccuracies during calculations.
- Adding Hydrogens: Add missing hydrogen atoms to ensure proper protonation. Keep in mind that if you’ve already added hydrogens based on a specific protonation, avoid overriding them.
SAMSON makes it simple to complete these steps seamlessly. Navigate to Home > Prepare and select the cleanup options in the dialog box as shown below:
What If Your Structure is Missing Residues or Atoms?
If your structure contains unresolved residues or missing heavy atoms, SAMSON provides an additional tool to fix these issues: the PDBFixer extension. PDBFixer helps you:
- Resolve incomplete protein chains.
- Fix missing atoms, like side-chain atoms.
- Add hydrogens customized for specific pH levels.
These features add flexibility to your preparation process and ensure your system is thoroughly optimized before docking.
Note
If you are using the tutorial sample file in SAMSON, all water molecules have already been removed, and hydrogens have already been added. Skip these steps if you work with this file.
Secondary Structure Visualization
Proper visualization can be crucial during system preparation to analyze structural alignments and ensure all components are positioned accurately. If secondary structures aren’t displayed by default, SAMSON allows you to add ribbons for visual clarity. Simply go to Visualization > Visual model > Ribbons after selecting the protein’s structural model in the Document view.
You can also toggle between an atomistic display and a ribbon model for convenience using the Document view interface.
Start Your Docking Workflow With Confidence
With SAMSON’s build-in tools, preparing your system for protein docking workflows becomes a streamlined process, helping you focus on obtaining meaningful docking results without being bogged down by preparatory challenges. To explore more about running Hex-based docking workflows from start to finish, visit the original documentation.
SAMSON and all SAMSON Extensions are free for non-commercial use. Download SAMSON at SAMSON Connect.